Assistant Secretary of the Air Force visits Edwards Published Feb. 2, 2012 EDWARDS AIR FORCE BASE, Calif. -- Terry A. Yonkers (center) Assistant Secretary of the Air Force for Installations, Environment and Logistics visits with David Harrell (right) a facilities specialist with the 95th Civil Engineering Division in the utility building on Jan. 19, 2012, as Col. Calvin Williams, senior military assistant with Yonkers looks on. Yonkers visited Ridley Mission Control Center, the Rosburg Fitness Center and newly constructed solar farms during his tour of base facilities.